RT-qPCR.

RT-qPCR was used to analyze mabB expression. Comamonas sp. QT12 was grown in 3-aminobenzoate and citrate-NH₄Cl as its sole sources of carbon and nitrogen, respectively. Total RNA was prepared using an RNAprep pure cell/bacteria kit according to the manufacturer's instructions. The cDNA was synthesized using All-In-One RT master mix (with AccuRT). The primers were mabB-q-F/mabB-q-R for mabB and 16S-q-F/16S-q-R for 16S rRNA. RT-qPCR was performed in a volume of 20 μl on a Stratagene Mx3000P PCR instrument (Agilent Technologies, Palo Alto, CA) with EvaGreen 2× PCR master mix and RT-qPCR primers. The threshold cycle (C_T) values for mabB were normalized to the expression level of the 16S rRNA gene. Expression levels were calculated according to the 2^-ΔΔCT method. Primers for RT-qPCR are listed in Table 3.

Oligonucleotides used in this study